Audio Technica Earphones are designed to provide noise isolation, so the ear tips should feel as snug as possible without feeling uncomfortable. Take the time to go up and down in size to make sure youre getting the best combination of comfort and audio clarity. If you can hear too much of the outside world around you, then the tip may be too small. On the other hand, if the ear tip hurts your ears over time its likely the ear tip is too large.